README.UPDATING: emphasise more the LDAP issue
[exim.git] / src / README.UPDATING
1 This document contains detailed information about incompatibilities that might
2 be encountered when upgrading from one release of Exim to another. The
3 information is in reverse order of release numbers. Mostly these are relatively
4 small points, and the configuration file is normally upwards compatible, but
5 there have been two big upheavals...
8 **************************************************************************
9 * There was a big reworking of the way mail routing works for release *
10 * 4.00. Previously used "directors" were abolished, and all routing is *
11 * now done by routers. Policy controls for incoming mail are now done by *
12 * Access Control Lists instead of separate options. All this means that *
13 * pre-4.00 configuration files have to be massively converted. If you *
14 * are coming from a 3.xx release, please read the document in the file *
15 * doc/Exim4.upgrade, and allow some time to complete the upgrade. *
16 * *
17 * There was a big reworking of the way domain/host/net/address lists are *
18 * handled at release 3.00. If you are coming from a pre-3.00 release, it *
19 * might be easier to start again from a default configuration. Otherwise *
20 * you need to read doc/Exim3.upgrade and do a double conversion of your *
21 * configuration file. *
22 **************************************************************************
25 The rest of this document contains information about changes in 4.xx releases
26 that might affect a running system.
29 Exim version 4.80
30 -----------------
32 * BEWARE backwards-incompatible changes in SSL libraries, thus the version
33 bump. See points below for details.
34 Also an LDAP data returned format change.
36 * The value of $tls_peerdn is now print-escaped when written to the spool file
37 in a -tls_peerdn line, and unescaped when read back in. We received reports
38 of values with embedded newlines, which caused spool file corruption.
40 If you have a corrupt spool file and you wish to recover the contents after
41 upgrading, then lock the message, replace the new-lines that should be part
42 of the -tls_peerdn line with the two-character sequence \n and then unlock
43 the message. No tool has been provided as we believe this is a rare
44 occurence.
46 * With OpenSSL 1.0.1+, Exim now supports TLS 1.1 and TLS 1.2. If built
47 against 1.0.1a then you will get a warning message and the
48 "openssl_options" value will not parse "no_tlsv1_1": the value changes
49 incompatibly between 1.0.1a and 1.0.1b, because the value chosen for 1.0.1a
50 is infelicitous. We advise avoiding 1.0.1a.
52 "openssl_options" gains "no_tlsv1_1", "no_tlsv1_2" and "no_compression".
54 COMPATIBILITY WARNING: The default value of "openssl_options" is no longer
55 "+dont_insert_empty_fragments". We default to unset. That old default was
56 grandfathered in from before openssl_options became a configuration option.
57 Empty fragments are inserted by default through TLS1.0, to partially defend
58 against certain attacks; TLS1.1+ change the protocol so that this is not
59 needed. The DIEF SSL option was required for some old releases of mail
60 clients which did not gracefully handle the empty fragments, and was
61 initially set in Exim release 4.31 (see ChangeLog, item 37).
63 If you still have affected mail-clients, and you see SSL protocol failures
64 with this release of Exim, set:
65 openssl_options = +dont_insert_empty_fragments
66 in the main section of your Exim configuration file. You're trading off
67 security for compatibility. Exim is now defaulting to higher security and
68 rewarding more modern clients.
70 If the option tls_dhparams is set and the parameters loaded from the file
71 have a bit-count greater than the new option tls_dh_max_bits, then the file
72 will now be ignored. If this affects you, raise the tls_dh_max_bits limit.
73 We suspect that most folks are using dated defaults and will not be affected.
75 * Ldap lookups returning multi-valued attributes now separate the attributes
76 with only a comma, not a comma-space sequence. Also, an actual comma within
77 a returned attribute is doubled. This makes it possible to parse the
78 attribute as a comma-separated list. Note the distinction from multiple
79 attributes being returned, where each one is a name=value pair.
81 If you are currently splitting the results from LDAP upon a comma, then you
82 should check carefully to see if adjustments are needed.
84 This change lets cautious folks distinguish "comma used as separator for
85 joining values" from "comma inside the data".
87 * accept_8bitmime now defaults on, which is not RFC compliant but is better
88 suited to today's Internet. See for a
89 sane rationale. Those who wish to be strictly RFC compliant, or know that
90 they need to talk to servers that are not 8-bit-clean, now need to take
91 explicit configuration action to default this option off. This is not a
92 new option, you can safely force it off before upgrading, to decouple
93 configuration changes from the binary upgrade while remaining RFC compliant.
95 * The GnuTLS support has been mostly rewritten, to use APIs which don't cause
96 deprecation warnings in GnuTLS 2.12.x. As part of this, these three options
97 are no longer supported:
99 gnutls_require_kx
100 gnutls_require_mac
101 gnutls_require_protocols
103 Their functionality is entirely subsumed into tls_require_ciphers. In turn,
104 tls_require_ciphers is no longer an Exim list and is not parsed by Exim, but
105 is instead given to gnutls_priority_init(3), which expects a priority string;
106 this behaviour is much closer to the OpenSSL behaviour. See:
110 for fuller documentation of the strings parsed. The three gnutls_require_*
111 options are still parsed by Exim and, for this release, silently ignored.
112 A future release will add warnings, before a later still release removes
113 parsing entirely and the presence of the options will be a configuration
114 error.
116 Note that by default, GnuTLS will not accept RSA-MD5 signatures in chains.
117 A tls_require_ciphers value of NORMAL:%VERIFY_ALLOW_SIGN_RSA_MD5 may
118 re-enable support, but this is not supported by the Exim maintainers.
119 Our test suite no longer includes MD5-based certificates.
121 This rewrite means that Exim will continue to build against GnuTLS in the
122 future, brings Exim closer to other GnuTLS applications and lets us add
123 support for SNI and other features more readily. We regret that it wasn't
124 feasible to retain the three dropped options.
126 * If built with TLS support, then Exim will now validate the value of
127 the main section tls_require_ciphers option at start-up. Before, this
128 would cause a STARTTLS 4xx failure, now it causes a failure to start.
129 Running with a broken configuration which causes failures that may only
130 be left in the logs has been traded off for something more visible. This
131 change makes an existing problem more prominent, but we do not believe
132 anyone would deliberately be running with an invalid tls_require_ciphers
133 option.
135 This also means that library linkage issues caused by conflicts of some
136 kind might take out the main daemon, not just the delivery or receiving
137 process. Conceivably some folks might prefer to continue delivering
138 mail plaintext when their binary is broken in this way, if there is a
139 server that is a candidate to receive such mails that does not advertise
140 STARTTLS. Note that Exim is typically a setuid root binary and given
141 broken linkage problems that cause segfaults, we feel it is safer to
142 fail completely. (The check is not done as root, to ensure that problems
143 here are not made worse by the check).
146 Exim version 4.77
147 -----------------
149 * GnuTLS will now attempt to use TLS 1.2 and TLS 1.1 before TLS 1.0 and SSL3,
150 if supported by your GnuTLS library. Use the existing
151 "gnutls_require_protocols" option to downgrade this if that will be a
152 problem. Prior to this release, supported values were "TLS1" and "SSL3",
153 so you should be able to update configuration prior to update.
155 [nb: gnutls_require_protocols removed in Exim 4.80, instead use
156 tls_require_ciphers to provide a priority string; see notes above]
158 * The match_<type>{string1}{string2} expansion conditions no longer subject
159 string2 to string expansion, unless Exim was built with the new
160 "EXPAND_LISTMATCH_RHS" option. Too many people have inadvertently created
161 insecure configurations that way. If you need the functionality and turn on
162 that build option, please let the developers know, and know why, so we can
163 try to provide a safer mechanism for you.
165 The match{}{} expansion condition (for regular expressions) is NOT affected.
166 For match_<type>{s1}{s2}, all list functionality is unchanged. The only
167 change is that a '$' appearing in s2 will not trigger expansion, but instead
168 will be treated as a literal $ sign; the effect is very similar to having
169 wrapped s2 with \N...\N. If s2 contains a named list and the list definition
170 uses $expansions then those _will_ be processed as normal. It is only the
171 point at which s2 is read where expansion is inhibited.
173 If you are trying to test if two email addresses are equal, use eqi{s1}{s2}.
174 If you are testing if the address in s1 occurs in the list of items given
175 in s2, either use the new inlisti{s1}{s2} condition (added in 4.77) or use
176 the pre-existing forany{s2}{eqi{$item}{s1}} condition.
179 Exim version 4.74
180 -----------------
182 * The integrated support for dynamically loadable lookup modules has an ABI
183 change from the modules supported by some OS vendors through an unofficial
184 patch. Don't try to mix & match.
186 * Some parts of the build system are now beginning to assume that the host
187 environment is POSIX. If you're building on a system where POSIX tools are
188 not the default, you might have an easier time if you switch to the POSIX
189 tools. Feel free to report non-POSIX issues as a request for a feature
190 enhancement, but if the POSIX variants are available then the fix will
191 probably just involve some coercion. See the README instructions for
192 building on such hosts.
195 Exim version 4.73
196 -----------------
198 * The Exim run-time user can no longer be root; this was always
199 strongly discouraged, but is now prohibited both at build and
200 run-time. If you need Exim to run routinely as root, you'll need to
201 patch the source and accept the risk. Here be dragons.
203 * Exim will no longer accept a configuration file owned by the Exim
204 run-time user, unless that account is explicitly the value in
205 CONFIGURE_OWNER, which we discourage. Exim now checks to ensure that
206 files are not writeable by other accounts.
208 * The ALT_CONFIG_ROOT_ONLY build option is no longer optional and is forced
209 on; the Exim user can, by default, no longer use -C/-D and retain privilege.
210 Two new build options mitigate this.
212 * TRUSTED_CONFIG_LIST defines a file containing a whitelist of config
213 files that are trusted to be selected by the Exim user; one per line.
214 This is the recommended approach going forward.
216 * WHITELIST_D_MACROS defines a colon-separated list of macro names which
217 the Exim run-time user may safely pass without dropping privileges.
218 Because changes to this involve a recompile, this is not the recommended
219 approach but may ease transition. The values of the macros, when
220 overridden, are constrained to match this regex: ^[A-Za-z0-9_/.-]*$
222 * The system_filter_user option now defaults to the Exim run-time user,
223 rather than root. You can still set it explicitly to root and this
224 can be done with prior versions too, letting you roll versions
225 without needing to change this configuration option.
227 * ClamAV must be at least version 0.95 unless WITH_OLD_CLAMAV_STREAM is
228 defined at build time.
231 Exim version 4.70
232 -----------------
234 1. Experimental Yahoo! Domainkeys support has been dropped in this release.
235 It has been superceded by a native implementation of its successor DKIM.
237 2. Up to version 4.69, Exim came with an embedded version of the PCRE library.
238 As of 4.70, this is no longer the case. To compile Exim, you will need PCRE
239 installed. Most OS distributions have ready-made library and development
240 packages.
243 Exim version 4.68
244 -----------------
246 1. The internal implementation of the database keys that are used for ACL
247 ratelimiting has been tidied up. This means that an update to 4.68 might cause
248 Exim to "forget" previous rates that it had calculated, and reset them to zero.
251 Exim version 4.64
252 -----------------
254 1. Callouts were setting the name used for EHLO/HELO from $smtp_active_
255 hostname. This is wrong, because it relates to the incoming message (and
256 probably the interface on which it is arriving) and not to the outgoing
257 callout (which could be using a different interface). This has been
258 changed to use the value of the helo_data option from the smtp transport
259 instead - this is what is used when a message is actually being sent. If
260 there is no remote transport (possible with a router that sets up host
261 addresses), $smtp_active_hostname is used. This change is mentioned here in
262 case somebody is relying on the use of $smtp_active_hostname.
264 2. A bug has been fixed that might just possibly be something that is relied on
265 in some configurations. In expansion items such as ${if >{xxx}{yyy}...} an
266 empty string (that is {}) was being interpreted as if it was {0} and therefore
267 treated as the number zero. From release 4.64, such strings cause an error
268 because a decimal number, possibly followed by K or M, is required (as has
269 always been documented).
271 3. There has been a change to the GnuTLS support (ChangeLog/PH/20) to improve
272 Exim's performance. Unfortunately, this has the side effect of being slightly
273 non-upwards compatible for versions 4.50 and earlier. If you are upgrading from
274 one of these earlier versions and you use GnuTLS, you must remove the file
275 called gnutls-params in Exim's spool directory. If you don't do this, you will
276 see this error:
278 TLS error on connection from ... (DH params import): Base64 decoding error.
280 Removing the file causes Exim to recompute the relevant encryption parameters
281 and cache them in the new format that was introduced for release 4.51 (May
282 2005). If you are upgrading from release 4.51 or later, there should be no
283 problem.
286 Exim version 4.63
287 -----------------
289 When an SMTP error message is specified in a "message" modifier in an ACL, or
290 in a :fail: or :defer: message in a redirect router, Exim now checks the start
291 of the message for an SMTP error code. This consists of three digits followed
292 by a space, optionally followed by an extended code of the form n.n.n, also
293 followed by a space. If this is the case and the very first digit is the same
294 as the default error code, the code from the message is used instead. If the
295 very first digit is incorrect, a panic error is logged, and the default code is
296 used. This is an incompatible change, but it is not expected to affect many (if
297 any) configurations. It is possible to suppress the use of the supplied code in
298 a redirect router by setting the smtp_error_code option false. In this case,
299 any SMTP code is quietly ignored.
302 Exim version 4.61
303 -----------------
305 1. The default number of ACL variables of each type has been increased to 20,
306 and it's possible to compile Exim with more. You can safely upgrade to this
307 release if you already have messages on the queue with saved ACL variable
308 values. However, if you downgrade from this release with messages on the queue,
309 any saved ACL values they may have will be lost.
311 2. The default value for rfc1413_query_timeout has been changed from 30s to 5s.
314 Exim version 4.54
315 -----------------
317 There was a problem with 4.52/TF/02 in that a "name=" option on control=
318 submission terminated at the next slash, thereby not allowing for slashes in
319 the name. This has been changed so that "name=" takes the rest of the string as
320 its data. It must therefore be the last option.
323 Version 4.53
324 ------------
326 If you are using the experimental Domain Keys support, you must upgrade to
327 at least libdomainkeys 0.67 in order to run this release of Exim.
330 Version 4.51
331 ------------
333 1. The format in which GnuTLS parameters are cached (in the file gnutls-params
334 in the spool directory) has been changed. The new format can also be generated
335 externally, so it is now possible to update the values from outside Exim. This
336 has been implemented in an upwards, BUT NOT downwards, compatible manner.
337 Upgrading should be seamless: when Exim finds that it cannot understand an
338 existing cache file, it generates new parameters and writes them to the cache
339 in the new format. If, however, you downgrade from 4.51 to a previous release,
340 you MUST delete the gnutls-params file in the spool directory, because the
341 older Exim will not recognize the new format.
343 2. When doing a callout as part of verifying an address, Exim was not paying
344 attention to any local part prefix or suffix that was matched by the router
345 that accepted the address. It now behaves in the same way as it does for
346 delivery: the affixes are removed from the local part unless
347 rcpt_include_affixes is set on the transport. If you have a configuration that
348 uses prefixes or suffixes on addresses that could be used for callouts, and you
349 want the affixes to be retained, you must make sure that rcpt_include_affixes
350 is set on the transport.
352 3. Bounce and delay warning messages no longer contain details of delivery
353 errors, except for explicit messages (e.g. generated by :fail:) and SMTP
354 responses from remote hosts.
357 Version 4.50
358 ------------
360 The exicyclog script has been updated to use three-digit numbers in rotated log
361 files if the maximum number to keep is greater than 99. If you are already
362 keeping more than 99, there will be an incompatible change when you upgrade.
363 You will probably want to rename your old log files to the new form before
364 running the new exicyclog.
367 Version 4.42
368 ------------
370 RFC 3848 specifies standard names for the "with" phrase in Received: header
371 lines when AUTH and/or TLS are in use. This is the "received protocol"
372 field. Exim used to use "asmtp" for authenticated SMTP, without any
373 indication (in the protocol name) for TLS use. Now it follows the RFC and
374 uses "esmtpa" if the connection is authenticated, "esmtps" if it is
375 encrypted, and "esmtpsa" if it is both encrypted and authenticated. These names
376 appear in log lines as well as in Received: header lines.
379 Version 4.34
380 ------------
382 Change 4.31/2 gave problems to data ACLs and local_scan() functions that
383 expected to see a Received: header. I have changed to yet another scheme. The
384 Received: header is now generated after the body is received, but before the
385 ACL or local_scan() is called. After they have run, the timestamp in the
386 Received: header is updated.
388 Thus, change (a) of 4.31/2 has been reversed, but change (b) is still true,
389 which is lucky, since I decided it was a bug fix.
392 Version 4.33
393 ------------
395 If an expansion in a condition on a "warn" statement fails because a lookup
396 defers, the "warn" statement is abandoned, and the next ACL statement is
397 processed. Previously this caused the whole ACL to be aborted.
400 Version 4.32
401 ------------
403 Change 4.31/2 has been reversed, as it proved contentious. Recipient callout
404 verification now uses <> in the MAIL command by default, as it did before. A
405 new callout option, "use_sender", has been added to request the other
406 behaviour.
409 Version 4.31
410 ------------
412 1. If you compile Exim to use GnuTLS, it now requires the use of release 1.0.0
413 or greater. The interface to the obsolete 0.8.x releases is no longer
414 supported. There is one externally visible change: the format for the
415 display of Distinguished Names now uses commas as a separator rather than a
416 slash. This is to comply with RFC 2253.
418 2. When a message is received, the Received: header line is now generated when
419 reception is complete, instead of at the start of reception. For messages
420 that take a long time to come in, this changes the meaning of the timestamp.
421 There are several side-effects of this change:
423 (a) If a message is rejected by a DATA or non-SMTP ACL, or by local_scan(),
424 the logged header lines no longer include the local Received: line,
425 because it has not yet been created. If the message is a non-SMTP one,
426 and the error is processed by sending a message to the sender, the copy
427 of the original message that is returned does not have an added
428 Received: line.
430 (b) When a filter file is tested using -bf, no additional Received: header
431 is added to the test message. After some thought, I decided that this
432 is a bug fix.
434 The contents of $received_for are not affected by this change. This
435 variable still contains the single recipient of a message, copied after
436 addresses have been rewritten, but before local_scan() is run.
438 2. Recipient callout verification, like sender verification, was using <> in
439 the MAIL FROM command. This isn't really the right thing, since the actual
440 sender may affect whether the remote host accepts the recipient or not. I
441 have changed it to use the actual sender in the callout; this means that
442 the cache record is now keyed on a recipient/sender pair, not just the
443 recipient address. There doesn't seem to be a real danger of callout loops,
444 since a callout by the remote host to check the sender would use <>.
447 Version 4.30
448 ------------
450 1. I have abolished timeout_DNS as an error that can be detected in retry
451 rules, because it has never worked. Despite the fact that it has been
452 documented since at least release 1.62, there was no code to support it.
453 If you have used it in your retry rules, you will now get a warning message
454 to the log and panic log. It is now treated as plain "timeout".
456 2. After discussion on the mailing list, Exim no longer adds From:, Date:, or
457 Message-Id: header lines to messages that do not originate locally, that is,
458 messages that have an associated sending host address.
460 3. When looking up a host name from an IP address, Exim now tries the DNS
461 first, and only if that fails does it use gethostbyaddr() (or equivalent).
462 This change was made because on some OS, not all the names are given for
463 addresses with multiple PTR records via the gethostbyaddr() interface. The
464 order of lookup can be changed by setting host_lookup_order.
467 Version 4.23
468 ------------
470 1. The new FIXED_NEVER_USERS build-time option creates a list of "never users"
471 that cannot be overridden. The default in the distributed EDITME is "root".
472 If for some reason you were (against advice) running deliveries as root, you
473 will have to ensure that FIXED_NEVER_USERS is not set in your
474 Local/Makefile.
476 2. The ${quote: operator now quotes an empty string, which it did not before.
478 3. Version 4.23 saves the contents of the ACL variables with the message, so
479 that they can be used later. If one of these variables contains a newline,
480 there will be a newline character in the spool that will not be interpreted
481 correctely by a previous version of Exim. (Exim ignores keyed spool file
482 items that it doesn't understand - precisely for this kind of problem - but
483 it expects them all to be on one line.)
485 So the bottom line is: if you have newlines in your ACL variables, you
486 cannot retreat from 4.23.
489 Version 4.21
490 ------------
492 1. The idea of the "warn" ACL verb is that it adds a header or writes to the
493 log only when "message" or "log_message" are set. However, if one of the
494 conditions was an address verification, or a call to a nested ACL, the
495 messages generated by the underlying test were being passed through. This
496 no longer happens. The underlying message is available in $acl_verify_
497 message for both "message" and "log_message" expansions, so it can be
498 passed through if needed.
500 2. The way that the $h_ (and $header_) expansions work has been changed by the
501 addition of RFC 2047 decoding. See the main documentation (the NewStuff file
502 until release 4.30, then the manual) for full details. Briefly, there are
503 now three forms:
505 $rh_xxx: and $rheader_xxx: give the original content of the header
506 line(s), with no processing at all.
508 $bh_xxx: and $bheader_xxx: remove leading and trailing white space, and
509 then decode base64 or quoted-printable "words" within the header text,
510 but do not do charset translation.
512 $h_xxx: and $header_xxx: attempt to translate the $bh_ string to a
513 standard character set.
515 If you have previously been using $h_ expansions to access the raw
516 characters, you should change to $rh_ instead.
518 3. When Exim creates an RFC 2047 encoded word in a header line, it labels it
519 with the default character set from the headers_charset option instead of
520 always using iso-8859-1.
522 4. If TMPDIR is defined in Local/Makefile (default in src/EDITME is
523 TMPDIR="/tmp"), Exim checks for the presence of an environment variable
524 called TMPDIR, and if it finds it is different, it changes its value.
526 5. Following a discussion on the list, the rules by which Exim recognises line
527 endings on incoming messages have been changed. The -dropcr and drop_cr
528 options are now no-ops, retained only for backwards compatibility. The
529 following line terminators are recognized: LF CRLF CR. However, special
530 processing applies to CR:
532 (i) The sequence CR . CR does *not* terminate an incoming SMTP message,
533 nor a local message in the state where . is a terminator.
535 (ii) If a bare CR is encountered in a header line, an extra space is added
536 after the line terminator so as not to end the header. The reasoning
537 behind this is that bare CRs in header lines are most likely either
538 to be mistakes, or people trying to play silly games.
540 6. The code for using daemon_smtp_port, local_interfaces, and the -oX options
541 has been reorganized. It is supposed to be backwards compatible, but it is
542 mentioned here just in case I've screwed up.
546 Version 4.20
547 ------------
549 1. I have tidied and re-organized the code that uses alarm() for imposing time
550 limits on various things. It shouldn't affect anything, but if you notice
551 processes getting stuck, it may be that I've broken something.
553 2. The "arguments" log selector now also logs the current working directory
554 when Exim is called.
556 3. An incompatible change has been made to the appendfile transport. This
557 affects the case when it is used for file deliveries that are set up by
558 .forward and filter files. Previously, any settings of the "file" or
559 "directory" options were ignored. It is hoped that, like the address_file
560 transport in the default configuration, these options were never in fact set
561 on such transports, because they were of no use.
563 Now, if either of these options is set, it is used. The path that is passed
564 by the router is in $address_file (this is not new), so it can be used as
565 part of a longer path, or modified in any other way that expansion permits.
567 If neither "file" nor "directory" is set, the behaviour is unchanged.
569 4. Related to the above: in a filter, if a "save" command specifies a non-
570 absolute path, the value of $home/ is pre-pended. This no longer happens if
571 $home is unset or is set to an empty string.
573 5. Multiple file deliveries from a filter or .forward file can never be
574 batched; the value of batch_max on the transport is ignored for file
575 deliveries. I'm assuming that nobody ever actually set batch_max on the
576 address_file transport - it would have had odd effects previously.
578 6. DESTDIR is the more common variable that ROOT for use when installing
579 software under a different root filing system. The Exim install script now
580 recognizes DESTDIR first; if it is not set, ROOT is used.
582 7. If DESTDIR is set when installing Exim, it no longer prepends its value to
583 the path of the system aliases file that appears in the default
584 configuration (when a default configuration is installed). If an aliases
585 file is actually created, its name *does* use the prefix.
588 Version 4.14
589 ------------
591 1. The default for the maximum number of unknown SMTP commands that Exim will
592 accept before dropping a connection has been reduced from 5 to 3. However, you
593 can now change the value by setting smtp_max_unknown_commands.
595 2. The ${quote: operator has been changed so that it turns newline and carriage
596 return characters into \n and \r, respectively.
598 3. The file names used for maildir messages now include the microsecond time
599 fraction as well as the time in seconds, to cope with systems where the process
600 id can be re-used within the same second. The format is now
602 <time>.H<microsec>P<pid>.<host>
604 This should be a compatible change, but is noted here just in case.
606 4. The rules for creating message ids have changed, to cope with systems where
607 the process id can be re-used within the same second. The format, however, is
608 unchanged, so this should not cause any problems, except as noted in the next
609 item.
611 5. The maximum value for localhost_number has been reduced from 255 to 16, in
612 order to implement the new message id rules. For operating systems that have
613 case-insensitive file systems (Cygwin and Darwin), the limit is 10.
615 6. verify = header_syntax was allowing unqualified addresses in all cases. Now
616 it allows them only for locally generated messages and from hosts that match
617 sender_unqualified_hosts or recipient_unqualified_hosts, respectively.
619 7. For reasons lost in the mists of time, when a pipe transport was run, the
620 environment variable MESSAGE_ID was set to the message ID preceded by 'E' (the
621 form used in Message-ID: header lines). The 'E' has been removed.
624 Version 4.11
625 ------------
627 1. The handling of lines in the configuration file has changed. Previously,
628 macro expansion was applied to logical lines, after continuations had been
629 joined on. This meant that it could not be used in .include lines, which are
630 handled as physical rather than logical lines. Macro expansion is now done on
631 physical lines rather than logical lines. This means there are two
632 incompatibilities:
634 (a) A macro that expands to # to turn a line into a comment now applies only
635 to the physical line where it appears. Previously, it would have caused
636 any following continuations also to be ignored.
638 (b) A macro name can no longer be split over the boundary between a line and
639 its continuation. Actually, this is more of a bug fix. :-)
641 2. The -D command line option must now all be within one command line item.
642 This makes it possible to use -D to set a macro to the empty string by commands
643 such as
645 exim -DABC ...
646 exim -DABC= ...
648 Previously, these items would have moved on to the next item on the command
649 line. To include spaces in a macro definition item, quotes must be used, in
650 which case you can also have spaces after -D and surrounding the equals. For
651 example:
653 exim '-D ABC = something' ...
655 3. The way that addresses that redirect to themselves are handled has been
656 changed, in order to fix an obscure bug. This should not cause any problems
657 except in the case of wanting to go back from a 4.11 (or later) release to an
658 earlier release. If there are undelivered messages on the spool that contain
659 addresses which redirect to themselves, and the redirected addresses have
660 already been delivered, you might get a duplicate delivery if you revert to an
661 earlier Exim.
663 4. The default way of looking up IP addresses for hosts in the manualroute and
664 queryprogram routers has been changed. If "byname" or "bydns" is explicitly
665 specified, there is no change, but if no method is specified, Exim now behaves
666 as follows:
668 First, a DNS lookup is done. If this yields anything other than
669 HOST_NOT_FOUND, that result is used. Otherwise, Exim goes on to try a call to
670 getipnodebyname() (or gethostbyname() on older systems) and the result of the
671 lookup is the result of that call.
673 This change has been made because it has been discovered that on some systems,
674 if a DNS lookup called via getipnodebyname() times out, HOST_NOT_FOUND is
675 returned instead of TRY_AGAIN. Thus, it is safest to try a DNS lookup directly
676 first, and only if that gives a definite "no such host" to try the local
677 function.
679 5. In fixing the minor security problem with pid_file_path, I have removed some
680 backwards-compatible (undocumented) code which was present to ease conversion
681 from Exim 3. In Exim 4, pid_file_path is a literal; in Exim 3 it was allowed to
682 contain "%s", which was replaced by the port number for daemons listening on
683 non-standard ports. In Exim 4, such daemons do not write a pid file. The
684 backwards compatibility feature was to replace "%s" by nothing if it occurred
685 in an Exim 4 setting of pid_file_path. The bug was in this code. I have solved
686 the problem by removing the backwards compatibility feature. Thus, if you still
687 have "%s" somewhere in a setting of pid_file_path, you should remove it.
689 6. There has been an extension to lsearch files. The keys in these files may
690 now be quoted in order to allow for whitespace and colons in them. This means
691 that if you were previously using keys that began with a doublequote, you will
692 now have to wrap them with extra quotes and escape the internal quotes. The
693 possibility that anybody is actually doing this seems extremely remote, but it
694 is documented just in case.
697 Version 4.10
698 ------------
700 The build-time parameter EXIWHAT_KILL_ARG has been renamed EXIWHAT_KILL_SIGNAL
701 to better reflect its function. The OS-specific files have been updated. Only
702 if you have explicitly set this in your Makefile (highly unlikely) do you need
703 to change anything.
705 ****